The present invention relates to a projector apparatus preferable for use in, for example, a rear projection television using transmission type liquid crystal panels, and particularly to realization of a projector apparatus so configured that a warm airflow upon cooling a PS conversion device (hereinafter referred to as PS converter) for aligning the polarization directions of the light from a light source lamp is exhausted and the cooling effect on the PS converter and an optical prism unit can be enhanced.
A rear projection television is so designed that the light from a light source lamp is made to be incident on an optical prism unit including red, green, and blue liquid crystal panels and a dichroic prism, whereby images can be projected on a screen. To be more specific, the light from the light source lamp is aligned in light polarization direction by a PS converter, before being incident on the optical prism unit including the liquid crystal panels and the dichroic prism.
The liquid crystal panels in the optical prism unit and the PS converter are heated to a high temperature by the light from the light source lamp. Particularly, the PS converter is a device directly receiving the light from the light source lamp and is therefore heated to a very high temperature, for example, around 75° C. In view of this, the liquid crystal panels and the PS converter are cooled by blowing air thereto from a cooling mechanism such as a sirocco fan.
Here, in relation to the above-mentioned projector apparatus, there has been disclosed a technology in which the optical prism unit having liquid crystal panels is cooled by a blower (see, for example, Japanese Patent Laid-open No. 2001-13589).
In the technology disclosed in the patent reference, the projector apparatus includes an optical system unit 2, a cooling fan 3 for cooling a light valve portion of the optical system unit 2 and the surroundings thereof, and an outer cabinet 4 to which the optical system unit 2 and the cooling fan 3 are mounted. A sirocco fan is used as the cooling fan 3, the airflow from the sirocco fan is guided through a duct 5 to the light valve and the surroundings thereof, and is distributed by airflow amount control means provided in the duct, to thereby effectively cool the light valve and the surroundings thereof.